Search Results for author: Mário A. T. Figueiredo

Found 34 papers, 10 papers with code

Cost-Sensitive Learning to Defer to Multiple Experts with Workload Constraints

no code implementations11 Mar 2024 Jean V. Alves, Diogo Leitão, Sérgio Jesus, Marco O. P. Sampaio, Javier Liébana, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

Learning to defer (L2D) aims to improve human-AI collaboration systems by learning how to defer decisions to humans when they are more likely to be correct than an ML classifier.

Fraud Detection

FiFAR: A Fraud Detection Dataset for Learning to Defer

1 code implementation20 Dec 2023 Jean V. Alves, Diogo Leitão, Sérgio Jesus, Marco O. P. Sampaio, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

Financial fraud detection is a high-stakes setting where algorithms and human experts often work in tandem; however, there are no publicly available datasets for L2D concerning this important application of human-AI teaming.

Benchmarking Decision Making +1

Fairness-Aware Data Valuation for Supervised Learning

no code implementations29 Mar 2023 José Pombal, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

Data valuation is a ML field that studies the value of training instances towards a given predictive task.

Active Learning Data Valuation +1

Distinguishing Cause from Effect on Categorical Data: The Uniform Channel Model

no code implementations14 Mar 2023 Mário A. T. Figueiredo, Catarina A. Oliveira

We select as the most likely causal direction the one in which the conditional pmf is closer to a uniform channel (UC).

Causal Discovery

Understanding Unfairness in Fraud Detection through Model and Data Bias Interactions

no code implementations13 Jul 2022 José Pombal, André F. Cruz, João Bravo, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

The unparalleled ability of machine learning algorithms to learn patterns from data also enables them to incorporate biases embedded within.

Decision Making Fairness +1

Human-AI Collaboration in Decision-Making: Beyond Learning to Defer

no code implementations27 Jun 2022 Diogo Leitão, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

Human-AI collaboration (HAIC) in decision-making aims to create synergistic teaming between human decision-makers and AI systems.

Decision Making Fairness +1

Prisoners of Their Own Devices: How Models Induce Data Bias in Performative Prediction

no code implementations27 Jun 2022 José Pombal, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

The unparalleled ability of machine learning algorithms to learn patterns from data also enables them to incorporate biases embedded within.

Fairness Fraud Detection

Differentiable Causal Discovery Under Latent Interventions

1 code implementation4 Mar 2022 Gonçalo R. A. Faria, André F. T. Martins, Mário A. T. Figueiredo

Recent work has shown promising results in causal discovery by leveraging interventional data with gradient-based methods, even when the intervened variables are unknown.

Causal Discovery Variational Inference

Sparse Continuous Distributions and Fenchel-Young Losses

1 code implementation4 Aug 2021 André F. T. Martins, Marcos Treviso, António Farinhas, Pedro M. Q. Aguiar, Mário A. T. Figueiredo, Mathieu Blondel, Vlad Niculae

In contrast, for finite domains, recent work on sparse alternatives to softmax (e. g., sparsemax, $\alpha$-entmax, and fusedmax), has led to distributions with varying support.

Audio Classification Question Answering +1

TimeSHAP: Explaining Recurrent Models through Sequence Perturbations

1 code implementation30 Nov 2020 João Bento, Pedro Saleiro, André F. Cruz, Mário A. T. Figueiredo, Pedro Bizarro

Although recurrent neural networks (RNNs) are state-of-the-art in numerous sequential decision-making tasks, there has been little research on explaining their predictions.

Decision Making Feature Importance +3

Control with adaptive Q-learning

1 code implementation3 Nov 2020 João Pedro Araújo, Mário A. T. Figueiredo, Miguel Ayala Botto

The main difference between AQL and SPAQL is that the latter learns time-invariant policies, where the mapping from states to actions does not depend explicitly on the time step.

OpenAI Gym Q-Learning +1

Variational Mixture of Normalizing Flows

no code implementations1 Sep 2020 Guilherme G. P. Freitas Pires, Mário A. T. Figueiredo

The present work overcomes this by using normalizing flows as components in a mixture model and devising an end-to-end training procedure for such a model.

Clustering Density Estimation +1

Equilibrium Propagation for Complete Directed Neural Networks

1 code implementation15 Jun 2020 Matilde Tristany Farinha, Sérgio Pequito, Pedro A. Santos, Mário A. T. Figueiredo

Artificial neural networks, one of the most successful approaches to supervised learning, were originally inspired by their biological counterparts.

Sparse and Continuous Attention Mechanisms

2 code implementations NeurIPS 2020 André F. T. Martins, António Farinhas, Marcos Treviso, Vlad Niculae, Pedro M. Q. Aguiar, Mário A. T. Figueiredo

Exponential families are widely used in machine learning; they include many distributions in continuous and discrete domains (e. g., Gaussian, Dirichlet, Poisson, and categorical distributions via the softmax transformation).

Machine Translation Question Answering +4

Can auto-encoders help with filling missing data?

no code implementations ICLR Workshop DeepDiffEq 2019 Marek Śmieja, Maciej Kołomycki, Łukasz Struski, Mateusz Juda, Mário A. T. Figueiredo

This paper introduces an approach to filling in missing data based on deep auto-encoder models, adequate to high-dimensional data exhibiting complex dependencies, such as images.

A Classification-Based Approach to Semi-Supervised Clustering with Pairwise Constraints

no code implementations18 Jan 2020 Marek Śmieja, Łukasz Struski, Mário A. T. Figueiredo

In this paper, we introduce a neural network framework for semi-supervised clustering (SSC) with pairwise (must-link or cannot-link) constraints.

Binary Classification Classification +2

End-to-End Learning of Video Compression Using Spatio-Temporal Autoencoders

no code implementations27 Sep 2018 Jorge Pessoa, Helena Aidos, Pedro Tomás, Mário A. T. Figueiredo

Deep learning (DL) is having a revolutionary impact in image processing, with DL-based approaches now holding the state of the art in many tasks, including image compression.

Image Compression Motion Estimation +1

Conditional Random Fields as Recurrent Neural Networks for 3D Medical Imaging Segmentation

2 code implementations19 Jul 2018 Miguel Monteiro, Mário A. T. Figueiredo, Arlindo L. Oliveira

In this paper, we test whether this algorithm, which was shown to improve semantic segmentation for 2D RGB images, is able to improve segmentation quality for 3D multi-modal medical images.

3D Medical Imaging Segmentation Segmentation +2

Scene-Adapted Plug-and-Play Algorithm with Guaranteed Convergence: Applications to Data Fusion in Imaging

no code implementations2 Jan 2018 Afonso M. Teodoro, José M. Bioucas-Dias, Mário A. T. Figueiredo

The recently proposed plug-and-play (PnP) framework allows leveraging recent developments in image denoising to tackle other, more involved, imaging inverse problems.

Deblurring Image Deblurring +1

Blind image deblurring using class-adapted image priors

no code implementations6 Sep 2017 Marina Ljubenović, Mário A. T. Figueiredo

Blind image deblurring (BID) is an ill-posed inverse problem, usually addressed by imposing prior knowledge on the (unknown) image and on the blurring filter.

Blind Image Deblurring Image Deblurring

Scene-adapted plug-and-play algorithm with convergence guarantees

no code implementations8 Feb 2017 Afonso M. Teodoro, José M. Bioucas-Dias, Mário A. T. Figueiredo

Recent frameworks, such as the so-called plug-and-play, allow us to leverage the developments in image denoising to tackle other, and more involved, problems in image processing.

Image Denoising

Image Restoration with Locally Selected Class-Adapted Models

no code implementations23 May 2016 Afonso M. Teodoro, José M. Bioucas-Dias, Mário A. T. Figueiredo

State-of-the-art algorithms for imaging inverse problems (namely deblurring and reconstruction) are typically iterative, involving a denoising operation as one of its steps.

Deblurring Denoising +1

Image Restoration and Reconstruction using Variable Splitting and Class-adapted Image Priors

no code implementations12 Feb 2016 Afonso M. Teodoro, José M. Bioucas-Dias, Mário A. T. Figueiredo

This paper proposes using a Gaussian mixture model as a prior, for solving two image inverse problems, namely image deblurring and compressive imaging.

Deblurring Denoising +2

The Ordered Weighted $\ell_1$ Norm: Atomic Formulation, Projections, and Algorithms

3 code implementations15 Sep 2014 Xiangrong Zeng, Mário A. T. Figueiredo

The ordered weighted $\ell_1$ norm (OWL) was recently proposed, with two different motivations: its good statistical properties as a sparsity promoting regularizer; the fact that it generalizes the so-called {\it octagonal shrinkage and clustering algorithm for regression} (OSCAR), which has the ability to cluster/group regression variables that are highly correlated.

Clustering regression

Decreasing Weighted Sorted $\ell_1$ Regularization

no code implementations11 Apr 2014 Xiangrong Zeng, Mário A. T. Figueiredo

We consider a new family of regularizers, termed {\it weighted sorted $\ell_1$ norms} (WSL1), which generalizes the recently introduced {\it octagonal shrinkage and clustering algorithm for regression} (OSCAR) and also contains the $\ell_1$ and $\ell_{\infty}$ norms as particular instances.

Clustering regression

Spectrometric differentiation of yeast strains using minimum volume increase and minimum direction change clustering criteria

1 code implementation28 Mar 2014 Nuno Fachada, Mário A. T. Figueiredo, Vitor V. Lopes, Rui C. Martins, Agostinho C.Rosa

This paper proposes new clustering criteria for distinguishing Saccharomyces cerevisiae (yeast) strains using their spectrometric signature.

Clustering

Exploiting Two-Dimensional Group Sparsity in 1-Bit Compressive Sensing

no code implementations20 Feb 2014 Xiangrong Zeng, Mário A. T. Figueiredo

The subgradient of the 2D one-sided $\ell_1$ (or $\ell_2$) penalty and the projection onto the $K$-sparsity and TV or MTV constraint can be computed efficiently, allowing the appliaction of algorithms of the {\it forward-backward splitting} (a. k. a.

Compressive Sensing Vocal Bursts Valence Prediction

Binary Fused Compressive Sensing: 1-Bit Compressive Sensing meets Group Sparsity

no code implementations20 Feb 2014 Xiangrong Zeng, Mário A. T. Figueiredo

We propose a new method, {\it binary fused compressive sensing} (BFCS), to recover sparse piece-wise smooth signals from 1-bit compressive measurements.

Compressive Sensing

Group-sparse Matrix Recovery

no code implementations20 Feb 2014 Xiangrong Zeng, Mário A. T. Figueiredo

We show that the proximity operator of 2OSCAR can be computed based on that of OSCAR.

Clustering regression

Robust Binary Fused Compressive Sensing using Adaptive Outlier Pursuit

no code implementations20 Feb 2014 Xiangrong Zeng, Mário A. T. Figueiredo

We propose a new method, {\it robust binary fused compressive sensing} (RoBFCS), to recover sparse piece-wise smooth signals from 1-bit compressive measurements.

Compressive Sensing

A novel sparsity and clustering regularization

no code implementations18 Oct 2013 Xiangrong Zeng, Mário A. T. Figueiredo

We propose a novel SPARsity and Clustering (SPARC) regularizer, which is a modified version of the previous octagonal shrinkage and clustering algorithm for regression (OSCAR), where, the proposed regularizer consists of a $K$-sparse constraint and a pair-wise $\ell_{\infty}$ norm restricted on the $K$ largest components in magnitude.

Clustering regression

Solving OSCAR regularization problems by proximal splitting algorithms

no code implementations24 Sep 2013 Xiangrong Zeng, Mário A. T. Figueiredo

The OSCAR regularizer has a non-trivial proximity operator, which limits its applicability.

Clustering

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